Low-Pressure Ultraviolet Photon Detector With Tmae Gas Photocathode

Results of the study of the properties of a low pressure multistep avalanche counnter with TMAE (tetrakis(dimethylamine)ethylene) as the photosensitive gas are presented. The optimization of parameters is discussed. Absolute gas amplification, drift velocity and diffusion of drifting photoelectrons in a low pressure gas and the efficiency of single photoelectron detection are measured. The practical multihit capability and spatial resolution are explored in view of possible application in a Cherenkov ring imaging with multipad wedge-and-strip cathode readout with flash ADCs. The present limit in spatial resolution is due to diffusion of drifting electrons in a low-pressure gas. For applications where photons are detected in a high-rate background of charged particles, the low-pressure operation has many advantages over the atmospheric pressure detectors.